Dialog boxes use radio buttons and check boxes to let the user choose from a list of options. Radio buttons let the user choose from mutually exclusive options; check boxes let the user pick a combination of options.
The dialog box procedure can set the initial state of a check box by using the CheckDlgButton function, which sets or clears the check box. For radio buttons in a group of mutually exclusive radio buttons, the dialog box procedure can use the CheckRadioButton function to set the appropriate radio button and automatically clear any other radio button.
Before a dialog box terminates, the dialog box procedure can check the state of each radio button and check box by using the IsDlgButtonChecked function, which returns the current state of the button. A dialog box typically saves this information to initialize the buttons the next time it creates the dialog box.